Post by themohawkninja on Aug 31, 2017 23:02:52 GMT

Hello,

I recently watched a video talking about how railguns are potentially not the best solution for modern militaries given that conventional artillery can provide the same destructive power on ground targets, and solid state lasers work great for shooting down missiles. It also pointed out that if it is possible, we are probably somewhat far off from the power requirements being small enough to allow for mounting on a tank or other such system.

It got me thinking though, would it be feasible to have a self-contained expendable railgun cartridge comprised of the projectile and a supercapacitor holding the required charge? If it could be made small enough, that would allow for anti-tank sized weaponry, which would be a great way to exploit the extremely high penetration that a railgun offers.

I just don't know enough about the math behind it to start looking into it. There's a force equation on the Wikipedia page that uses amperage, armature length, and field strength, but I don't really know enough about electricity to have a clue how to tackle the issue, if the answer is even within the ballpark of current technology.

Post by Enderminion on Aug 31, 2017 23:06:02 GMT

you have to squish the capacitor and ammo into the turret of a M1 pattern main battle tank, and it has to reload in ~6 seconds, and run off the M1's power plant (1.12Mw, use less so it can move and shoot) and you need multi-kilo projectiles, you can use shaped railgun armature projectiles though. it also needs to beat 14Mj of muzzle energy

Post by OMGitsWTF on Aug 31, 2017 23:12:50 GMT

I recently watched a video talking about how railguns are potentially not the best solution for modern militaries given that conventional artillery can provide the same destructive power on ground targets, and solid state lasers work great for shooting down missiles. It also pointed out that if it is possible, we are probably somewhat far off from the power requirements being small enough to allow for mounting on a tank or other such system.

It got me thinking though, would it be feasible to have a self-contained expendable railgun cartridge comprised of the projectile and a supercapacitor holding the required charge? If it could be made small enough, that would allow for anti-tank sized weaponry, which would be a great way to exploit the extremely high penetration that a railgun offers.

I just don't know enough about the math behind it to start looking into it. There's a force equation on the Wikipedia page that uses amperage, armature length, and field strength, but I don't really know enough about electricity to have a clue how to tackle the issue, if the answer is even within the ballpark of current technology.

Current supercapacitors have energy densities of 10kj/kg. We need an 30 times increase to allow an 10kg supercapacitor to produce enough power to accelerate an 1kg projectile to Mach 7 or 2.4km/s. An Flywheel could, if made out of high GPa materials have energy densities superior to high explosives. That might allow this. This assumes 100% efficent railguns. The navy railgun is supposed to have 33%.

Post by Enderminion on Aug 31, 2017 23:52:21 GMT

Try making the system in CoaDE, I'd say. If it works in game, I'd give it at least a 50% chance to work in real life.

I managed to get 14Mj (roughly APDS muzzle energy) out of a railgun, it would need two of Apophys 100Mw reactors to fire often enough and radiate over a gigawatt of heat, but the railgun, powerplant, and 18000 6kg rounds could fit into the turret of a M1 series tank (most likely, I could not find the cubage of that tanks turret so I assumed 24m^3)

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Post by RiftandRend on Sept 1, 2017 6:11:02 GMT

Try making the system in CoaDE, I'd say. If it works in game, I'd give it at least a 50% chance to work in real life.

I managed to get 14Mj (roughly APDS muzzle energy) out of a railgun, it would need two of Apophys 100Mw reactors to fire often enough and radiate over a gigawatt of heat, but the railgun, powerplant, and 18000 6kg rounds could fit into the turret of a M1 series tank (most likely, I could not find the cubage of that tanks turret so I assumed 24m^3)

If this is for use on earth you can set your reactor output temp at ~300K. The atmosphere is an amazing heat sink.

Post by Enderminion on Sept 1, 2017 17:10:46 GMT

I managed to get 14Mj (roughly APDS muzzle energy) out of a railgun, it would need two of Apophys 100Mw reactors to fire often enough and radiate over a gigawatt of heat, but the railgun, powerplant, and 18000 6kg rounds could fit into the turret of a M1 series tank (most likely, I could not find the cubage of that tanks turret so I assumed 24m^3)

If this is for use on earth you can set your reactor output temp at ~300K. The atmosphere is an amazing heat sink.

I could, or I could keep it more then 2k kelvins to cook enemy infantry

Post by OMGitsWTF on Sept 1, 2017 17:18:20 GMT

Try making the system in CoaDE, I'd say. If it works in game, I'd give it at least a 50% chance to work in real life.

I managed to get 14Mj (roughly APDS muzzle energy) out of a railgun, it would need two of Apophys 100Mw reactors to fire often enough and radiate over a gigawatt of heat, but the railgun, powerplant, and 18000 6kg rounds could fit into the turret of a M1 series tank (most likely, I could not find the cubage of that tanks turret so I assumed 24m^3)

So you gonna put 1.4t Capacitors, nuclear reactors and a high power waste heat system into an M1 Abrams for what reason? Does it have any advantage so major that it would be worth the extra price and complexity?

Post by Enderminion on Sept 1, 2017 17:24:34 GMT

I managed to get 14Mj (roughly APDS muzzle energy) out of a railgun, it would need two of Apophys 100Mw reactors to fire often enough and radiate over a gigawatt of heat, but the railgun, powerplant, and 18000 6kg rounds could fit into the turret of a M1 series tank (most likely, I could not find the cubage of that tanks turret so I assumed 24m^3)

So you gonna put 1.4t Capacitors, nuclear reactors and a high power waste heat system into an M1 Abrams for what reason? Does it have any advantage so major that it would be worth the extra price and complexity?

Post by OMGitsWTF on Sept 1, 2017 17:30:31 GMT

So you gonna put 1.4t Capacitors, nuclear reactors and a high power waste heat system into an M1 Abrams for what reason? Does it have any advantage so major that it would be worth the extra price and complexity?

Stats or didn't happen. You could replace the nuclear reactor with an CNT flywheel. 1.75t 2.1m diameter 25cm height. 350GJ of energy. Or with some carbon fiber at one to two magnitudes lower energy densities.

Post by Enderminion on Sept 1, 2017 18:33:41 GMT

Stats or didn't happen. You could replace the nuclear reactor with an CNT flywheel. 1.75t 2.1m diameter 25cm height. 350GJ of energy. Or with some carbon fiber at one to two magnitudes lower energy densities.

although with the power plant needed you could mount a fairly hefty laser, also masses as much as a tank

Post by OMGitsWTF on Sept 1, 2017 18:58:15 GMT

Stats or didn't happen. You could replace the nuclear reactor with an CNT flywheel. 1.75t 2.1m diameter 25cm height. 350GJ of energy. Or with some carbon fiber at one to two magnitudes lower energy densities.

although with the power plant needed you could mount a fairly hefty laser, also masses as much as a tank

Post by RiftandRend on Sept 1, 2017 19:07:43 GMT

If this is for use on earth you can set your reactor output temp at ~300K. The atmosphere is an amazing heat sink.

I could, or I could keep it more then 2k kelvins to cook enemy infantry

What I am saying is that it would not be 2000 kelvin. The atmosphere is far too effective a heat sink and would cool it very fast. Your reactors output temperature would be far closer to 300K than 2000K.

Post by Enderminion on Sept 1, 2017 19:12:49 GMT

I could, or I could keep it more then 2k kelvins to cook enemy infantry

What I am saying is that it would not be 2000 kelvin. The atmosphere is far too effective a heat sink and would cool it very fast. Your reactors output temperature would be far closer to 300K than 2000K.

ah, I didn't know what you were trying to say at first, sorrey

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